Ireland captain Rory Best has told his side to embrace the "massive challenge" of trying to win a Grand Slam against England on Saturday and forget about any Twickenham fear factor.

The Irish have already ensured they will displace England as champions last weekend - their third Six Nations title in five years under Kiwi coach Joe Schmidt. Now they are 80 minutes away from completing only their third Championship clean sweep, after the 1948 and 2009 slams.

"Everyone's aware of the significance," Best told reporters at Twickenham on Friday.

"You want to put yourself in position to win things," the hooker added.

"Now we've got the chance to pit ourselves against what has been the best team in the northern hemisphere for the last two years.

"So it's a massive challenge for us, and it is one that we're really excited about."

England come into the game on the back of successive away defeats by both Scotland and France and are under pressure as never before since Eddie Jones took charge following their 2015 Rugby World Cup debacle.

Nevertheless, they have yet to lose a Test at Twickenham under Australian coach in a run of 14 straight home wins at "headquarters".

Ireland haven't won at Twickenham since 2010.

"England are a quality side, and disputing that would be madness," said Best. "It's becoming very difficult to win anywhere away from home now.

They've yet to lose here under Eddie Jones. Twickenham is a big fortress - there's no point trying to hide away from that."

But, equally, Best said there was no point in Ireland being over-awed by England's home record.

"Tomorrow at quarter to three (the match kicks off at 1445GMT) is not the time to go into your shell," the 35-year-old Ulster front row said.

Twickenham is set for an 82,000 sell-out, with Best hoping that some of the tens of thousands of Irish spectators who have been cheering on their horses at this week's Cheltenham Festival meeting in southwest England will make the journey to London for another major sporting occasion.

"They pack so many people in, and like most teams, England get a lift from that.

"It's important we'll get a position to quieten the crowd, and we get as many Irishmen who wander down the road from Cheltenham standing on their feet as we can.

"And the only way to do that is for us to perform and be big in the game.

"You always have that consolation prize of the Championship, but having put ourselves in this position we want to go on and achieve something special," he added.

Best and fullback Rob Kearney are the only survivors from the 2009 side, although Best was then the reserve hooker.

"It's hard to remember that far back at this stage," said Best.

"For me personally yeah, there's a little more pressure. There's always more pressure when you start, but there's more pressure as captain as well - on the subs' bench you don't know if you'll come on at all."